Text (ODPS SDK Commons for Mapreduce/Graph 0.45.2-public API)

java.lang.Object
- com.aliyun.odps.io.BinaryComparable
- - com.aliyun.odps.io.Text

All Implemented Interfaces:

Writable, WritableComparable<BinaryComparable>, Comparable<BinaryComparable>

Direct Known Subclasses:

CharWritable, VarcharWritable
```
public class Text
extends BinaryComparable
implements WritableComparable<BinaryComparable>
```
Text 提供了字符串的 Writable 和 WritableComparable 的实现.
Text 内部使用字节数组保存字符串，并采用 UTF-8 编码，提供了序列化、反序列化以及字节级别的字符串比较方法。
另外，Text 也提供了一组丰富的字符串处理函数。

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class Text.Comparator
Text 对象的 WritableComparator 自然顺序实现（升序）.

Nested Classes
Modifier and Type	Class and Description
`static class`	`Text.Comparator` Text 对象的 `WritableComparator` 自然顺序实现（升序）.

Constructor Summary

Constructors
Constructor and Description
`Text()` 默认构造空串的 Text.
`Text(byte[] utf8)` 给定字节数组构造 Text
`Text(String string)` 给定字符串构造一个 Text.
`Text(Text utf8)` 从另一个 Text 对象构造 Text，内容会做拷贝.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`append(byte[] utf8, int start, int len)` 追加字符串内容.
`static int`	`bytesToCodePoint(ByteBuffer bytes)` Returns the next code point at the current position in the buffer.
`int`	`charAt(int position)` 返回给定位置 position 的 Unicode 32位标量值（Unicode scalar value）.
`void`	`clear()` 清空字符串，清空后 `getLength()` 返回0
`static String`	`decode(byte[] utf8)` Converts the provided byte array to a String using the UTF-8 encoding.
`static String`	`decode(byte[] utf8, int start, int length)`
`static String`	`decode(byte[] utf8, int start, int length, boolean replace)` Converts the provided byte array to a String using the UTF-8 encoding.
`static ByteBuffer`	`encode(String string)` Converts the provided String to bytes using the UTF-8 encoding.
`static ByteBuffer`	`encode(String string, boolean replace)` Converts the provided String to bytes using the UTF-8 encoding.
`boolean`	`equals(Object o)` Returns true iff `o` is a Text with the same contents.
`int`	`find(String what)` 查找子串出现的位置.
`int`	`find(String what, int start)` 从某个起始位置开始查找子串出现的位置
`byte[]`	`getBytes()` 返回存储字符串内容的字节数组，注意字节数组的有效内容是：0 ~ `getLength()`.
`int`	`getLength()` 获取内容长度，单位：字节
`int`	`hashCode()` 计算二进制内容的哈希值.
`void`	`readFields(ByteBuffer bf)`
`void`	`readFields(DataInput in)` 从指定的 `DataInput` in 反序列化.
`static String`	`readString(DataInput in)` Read a UTF8 encoded string from in
`void`	`set(byte[] utf8)` 给定 UTF-8 编码数组设置字符串内容.
`void`	`set(byte[] utf8, int start, int len)` 设置字符串内容.
`void`	`set(String string)` 给定 String 设置字符串内容.
`void`	`set(Text other)` 拷贝另个 Text 的内容.
`static void`	`skip(DataInput in)` Skips over one Text in the input.
`String`	`toString()` Convert text back to string
`static int`	`utf8Length(String string)` For the given string, returns the number of UTF-8 bytes required to encode the string.
`static void`	`validateUTF8(byte[] utf8)` Check if a byte array contains valid utf-8
`static void`	`validateUTF8(byte[] utf8, int start, int len)` Check to see if a byte array is valid utf-8
`void`	`write(DataOutput out)` 序列化到指定的 `DataOutput` out.
`static int`	`writeString(DataOutput out, String s)` Write a UTF8 encoded string to out

Methods inherited from class com.aliyun.odps.io.BinaryComparable
compareTo, compareTo

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Comparable
compareTo

- Constructor Detail
  - Text
```
public Text()
```
    默认构造空串的 Text.
  - Text
```
public Text(String string)
```
    给定字符串构造一个 Text.
    
    Parameters:
    
    string -
  - Text
```
public Text(Text utf8)
```
    从另一个 Text 对象构造 Text，内容会做拷贝.
    
    Parameters:
    
    string -
  - Text
```
public Text(byte[] utf8)
```
    给定字节数组构造 Text
    
    Parameters:
    
    utf8 -
- Method Detail
  - getBytes
```
public byte[] getBytes()
```
    返回存储字符串内容的字节数组，注意字节数组的有效内容是：0 ~ getLength(). 注意：字节数组的有效内容是：0 ~ getLength() ！直接使用整个字节数组可能会读到无效内容。
    
    Specified by:
    
    getBytes in class BinaryComparable
    
    Returns:
    
    二进制内容数组
    
    See Also:
    
    getLength()
  - getLength
```
public int getLength()
```
    获取内容长度，单位：字节
    
    Specified by:
    
    getLength in class BinaryComparable
    
    Returns:
    
    二进制内容长度，单位：字节
    
    See Also:
    
    getBytes()
  - charAt
```
public int charAt(int position)
```
    返回给定位置 position 的 Unicode 32位标量值（Unicode scalar value）.
    Text 内部使用字节数组保存字符串，并采用 UTF-8 编码，charAt 方法将字节数组在 position 位置的 UTF-8 字符转换为 Unicode 32位标量值并返回
    
    Returns:
    
    position 位置的 Unicode 32位标量值（Unicode scalar value），如果 position 无效（position < 0 或 position >= getLength()），则返回-1
    
    See Also:
    
    getBytes(), getLength()
  - find
```
public int find(String what)
```
    查找子串出现的位置.
    等价于 find(what, 0);
    
    Returns:
    
    如果找到，返回子串第一次出现在字节数组的位置，如果为找到，返回-1
  - find
```
public int find(String what,
                int start)
```
    从某个起始位置开始查找子串出现的位置
    
    Returns:
    
    如果找到，返回子串第一次出现在字节数组的位置，如果为找到，返回-1
  - set
```
public void set(String string)
```
    给定 String 设置字符串内容.
    
    Parameters:
    
    string -
  - set
```
public void set(byte[] utf8)
```
    给定 UTF-8 编码数组设置字符串内容.
    
    Parameters:
    
    utf8 -
  - set
```
public void set(Text other)
```
    拷贝另个 Text 的内容.
    
    Parameters:
    
    other -
  - set
```
public void set(byte[] utf8,
                int start,
                int len)
```
    设置字符串内容.
    
    Parameters:
    
    utf8 - 待拷贝内容的字节数组
    
    start - 待拷贝内容的起始位置
    
    len - 待拷贝内容的长度
  - append
```
public void append(byte[] utf8,
                   int start,
                   int len)
```
    追加字符串内容.
    
    Parameters:
    
    utf8 - 待追加内容的字节数组
    
    start - 待追加内容的起始位置
    
    len - 待追加内容的长度
  - clear
```
public void clear()
```
    清空字符串，清空后 getLength() 返回0
  - toString
```
public String toString()
```
    Convert text back to string
    
    Overrides:
    
    toString in class Object
    
    See Also:
    
    Object.toString()
  - readFields
```
public void readFields(DataInput in)
                throws IOException
```
    Description copied from interface: Writable
    
    从指定的 DataInput in 反序列化.
    
    Specified by:
    
    readFields in interface Writable
    
    Throws:
    
    IOException
  - readFields
```
public void readFields(ByteBuffer bf)
```
  - skip
```
public static void skip(DataInput in)
                 throws IOException
```
    Skips over one Text in the input.
    
    Throws:
    
    IOException
  - write
```
public void write(DataOutput out)
           throws IOException
```
    Description copied from interface: Writable
    
    序列化到指定的 DataOutput out.
    
    Specified by:
    
    write in interface Writable
    
    Throws:
    
    IOException
  - equals
```
public boolean equals(Object o)
```
    Returns true iff o is a Text with the same contents.
    
    Overrides:
    
    equals in class BinaryComparable
    
    Returns:
    
    如果两个都是 BinaryComparable 且内容相同，返回true，否则返回false
  - hashCode
```
public int hashCode()
```
    Description copied from class: BinaryComparable
    
    计算二进制内容的哈希值.
    直接使用 {@link WritableComparator#hashBytes(byte[], int)进行计算
    
    Overrides:
    
    hashCode in class BinaryComparable
  - decode
```
public static String decode(byte[] utf8)
                     throws CharacterCodingException
```
    Converts the provided byte array to a String using the UTF-8 encoding. If the input is malformed, replace by a default value.
    
    Throws:
    
    CharacterCodingException
  - decode
```
public static String decode(byte[] utf8,
                            int start,
                            int length)
                     throws CharacterCodingException
```
    Throws:
    
    CharacterCodingException
  - decode
```
public static String decode(byte[] utf8,
                            int start,
                            int length,
                            boolean replace)
                     throws CharacterCodingException
```
    Converts the provided byte array to a String using the UTF-8 encoding. If replace is true, then malformed input is replaced with the substitution character, which is U+FFFD. Otherwise the method throws a MalformedInputException.
    
    Throws:
    
    CharacterCodingException
  - encode
```
public static ByteBuffer encode(String string)
                         throws CharacterCodingException
```
    Converts the provided String to bytes using the UTF-8 encoding. If the input is malformed, invalid chars are replaced by a default value.
    
    Returns:
    
    ByteBuffer: bytes stores at ByteBuffer.array() and length is ByteBuffer.limit()
    
    Throws:
    
    CharacterCodingException
  - encode
```
public static ByteBuffer encode(String string,
                                boolean replace)
                         throws CharacterCodingException
```
    Converts the provided String to bytes using the UTF-8 encoding. If replace is true, then malformed input is replaced with the substitution character, which is U+FFFD. Otherwise the method throws a MalformedInputException.
    
    Returns:
    
    ByteBuffer: bytes stores at ByteBuffer.array() and length is ByteBuffer.limit()
    
    Throws:
    
    CharacterCodingException
  - readString
```
public static String readString(DataInput in)
                         throws IOException
```
    Read a UTF8 encoded string from in
    
    Throws:
    
    IOException
  - writeString
```
public static int writeString(DataOutput out,
                              String s)
                       throws IOException
```
    Write a UTF8 encoded string to out
    
    Throws:
    
    IOException
  - validateUTF8
```
public static void validateUTF8(byte[] utf8)
                         throws MalformedInputException
```
    Check if a byte array contains valid utf-8
    
    Parameters:
    
    utf8 - byte array
    
    Throws:
    
    MalformedInputException - if the byte array contains invalid utf-8
  - validateUTF8
```
public static void validateUTF8(byte[] utf8,
                                int start,
                                int len)
                         throws MalformedInputException
```
    Check to see if a byte array is valid utf-8
    
    Parameters:
    
    utf8 - the array of bytes
    
    start - the offset of the first byte in the array
    
    len - the length of the byte sequence
    
    Throws:
    
    MalformedInputException - if the byte array contains invalid bytes
  - bytesToCodePoint
```
public static int bytesToCodePoint(ByteBuffer bytes)
```
    Returns the next code point at the current position in the buffer. The buffer's position will be incremented. Any mark set on this buffer will be changed by this method!
  - utf8Length
```
public static int utf8Length(String string)
```
    For the given string, returns the number of UTF-8 bytes required to encode the string.
    
    Parameters:
    
    string - text to encode
    
    Returns:
    
    number of UTF-8 bytes required to encode

Class Text

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class com.aliyun.odps.io.BinaryComparable

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Comparable

Constructor Detail

Text

Text

Text

Text

Method Detail

getBytes

getLength

charAt

find

find

set

set

set

set

append

clear

toString

readFields

readFields

skip

write

equals

hashCode

decode

decode

decode

encode

encode

readString

writeString

validateUTF8

validateUTF8

bytesToCodePoint

utf8Length